function addSlot(Slot $slot)
{
if ($this->isSlotsAvailable()) {
$this->total += $slot->getPeriod()->i;
$slot->setTime(new \DateTime($this->timeIndex->format('H:i')));
$this->slots[] = $slot;
$this->timeIndex = $this->timeIndex->add($slot->getPeriod());
}
return $this;
}